scholarly journals Free-radical degradation of high-molar-mass hyaluronan induced by ascorbate plus cupric ions: Testing of stobadine and its two derivatives in function as antioxidants

2012 ◽  
Vol 31 (01) ◽  
pp. 57-64 ◽  
Author(s):  
Lubica Surovcikova-Machova ◽  
Katarina Valachova ◽  
Maria Banasova ◽  
Vladimir Snirc ◽  
Elena Priesolova ◽  
...  
Keyword(s):  
Free Radical ◽  
Molar Mass ◽  
High Molar Mass ◽  
Radical Degradation

Aurothiomalate as Preventive and Chain-Breaking Antioxidant in Radical Degradation of High-Molar-Mass Hyaluronan

2011 ◽  
Vol 8 (7) ◽  
pp. 1274-1283 ◽  
Author(s):  
Katarína Valachová ◽  
Andrea Vargová ◽  
Peter Rapta ◽  
Eva Hrabárová ◽  
František Dráfi ◽  
...  
Keyword(s):  
Molar Mass ◽  
High Molar Mass ◽  
Radical Degradation ◽  
Chain Breaking

Dithiols as more effective than monothiols in protecting biomacromolecules from free-radical-mediated damage: in vitro oxidative degradation of high-molar-mass hyaluronan

2014 ◽  
Vol 68 (10) ◽  
Author(s):  
Mária Baňasová ◽  
Katarína Valachová ◽  
Ivo Juránek ◽  
Ladislav Šoltés
Keyword(s):  
Free Radical ◽  
Molar Mass ◽  
Radical Scavenging ◽  
Oxidative Degradation ◽  
Free Radical Scavenging ◽  
Dpph Assay ◽  
High Molar Mass ◽  
High Concentrations ◽  
Free Radical Scavenging Activities

AbstractOxidative stress and the resulting damage to cellular and extracellular components has been observed in a variety of degenerative processes, including degenerative joint disorders, where high-molar-mass hyaluronan (HA) is often found to be massively degraded. The present study sought to test the hypothesis that dithiols are more effective in protecting biomacromolecules from free-radicalmediated damage than monothiols. The materials/thiols tested included bucillamine (BUC), dithioerythritol (DTE), dithiothreitol (DTT) and glutathione (GSH), as a reference, for their effectiveness in protecting HA from oxidative degradation induced in vitro. Since HA degradation results in a decrease in its dynamic viscosity, rotational viscometry was applied to follow HA oxidative degradation. The free-radical-scavenging activities of the thiols tested were determined by 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) assays. It was found that all the dithiols in the concentration range tested protected HA from the oxidative degradation. On the other hand, monothiol GSH exerted protection only at high concentrations (10 μmol L−1 and 100 μmol L−1) and 1 μmol L−1 of GSH even exhibited a prodegradative effect. The ABTS assay revealed free-radical scavenging activities in the following order: BUC, DTT, DTE, GSH, and that of the DPPH assay: BUC, DTE, DTT, GSH. In conclusion, it was demonstrated that dithiols may be more effective than monothiols in affording biomacromolecule protection from oxidative degradation.

ChemInform Abstract: Radical Degradation of High Molar Mass Hyaluronan Induced by Ascorbate Plus Cupric Ions Testing of Arbutin in the Function of Antioxidant

ChemInform ◽  
2013 ◽  
Vol 44 (51) ◽  
pp. no-no
Author(s):  
K. Valachova ◽  
P. Rapta ◽  
M. Slovakova ◽  
E. Priesolova ◽  
M. Nagy ◽  
...  
Keyword(s):  
Molar Mass ◽  
High Molar Mass ◽  
Radical Degradation

scholarly journals Effect of Bucillamine on Free-Radical-Mediated Degradation of High-Molar-Mass Hyaluronan Induced in vitro by Ascorbic Acid and Cu(II) Ions

Polymers ◽  
2014 ◽  
Vol 6 (10) ◽  
pp. 2625-2644 ◽  
Author(s):  
Mária Baňasová ◽  
Katarína Valachová ◽  
Jozef Rychlý ◽  
Ivica Janigová ◽  
Katarína Csomorová ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Free Radical ◽  
Molar Mass ◽  
High Molar Mass

Paper Chemistry: Interactions of thermo mechanical pulp fractions with high molar mass cationic polyacrylamides: Part 2. Flocculation

2010 ◽  
Vol 25 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Tero Taipale ◽  
Janne Laine ◽  
Susanna Holappa ◽  
Jonni Ahlgren ◽  
Juan Cecchini
Keyword(s):  
Molar Mass ◽  
High Molar Mass ◽  
Mechanical Pulp ◽  
Paper Chemistry

scholarly journals Highly Efficient MOF Catalyst Systems for CO2 Conversion to Bis-Cyclic Carbonates as Building Blocks for NIPHUs (Non-Isocyanate Polyhydroxyurethanes) Synthesis

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 628
Author(s):  
Adolfo Benedito ◽  
Eider Acarreta ◽  
Enrique Giménez
Keyword(s):  
Molar Mass ◽  
Cycloaddition Reaction ◽  
Building Blocks ◽  
Catalyst System ◽  
Cyclic Carbonate ◽  
Ammonium Bromide ◽  
Cyclic Carbonates ◽  
High Molar Mass ◽  
Highly Efficient ◽  
Free Process

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.

scholarly journals High Molar Mass Polycarbonate via Dynamic Solution Transcarbonation Using Bis(methyl salicyl) Carbonate, an Activated Carbonate

2021 ◽  
pp. 2100186
Author(s):  
Annelore Aerts ◽  
Camiel Kroonen ◽  
Jan Henk Kamps ◽  
Rint P. Sijbesma ◽  
Johan P. A. Heuts
Keyword(s):  
Molar Mass ◽  
High Molar Mass ◽  
Dynamic Solution

Synthesis of high molar mass poly(12-hydroxydodecanoic acid) in brønsted acid ionic liquids

Polymer ◽  
2010 ◽  
Vol 51 (6) ◽  
pp. 1218-1221 ◽  
Author(s):  
Elise-Marie Dukuzeyezu ◽  
Hervé Lefebvre ◽  
Martine Tessier ◽  
Alain Fradet
Keyword(s):  
Ionic Liquids ◽  
Molar Mass ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
High Molar Mass ◽  
Brönsted Acid
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